c-Myb-dependent smooth muscle cell differentiation.

Both in vitro and in vivo studies have implicated the c-Myb transcription factor in vascular smooth muscle cell (SMC) proliferation and hematopoiesis. However, its role in differentiation and maturation of contractile, as opposed to proliferating, SMCs has not been investigated. Here we demonstrate that c-myb(-/-) embryonic stem cells (ESCs) are incapable of producing embryoid bodies (EBs) with spontaneously contracting SMCs but can differentiate into contracting cardiomyocytes unimpaired.